package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * Redis 自增ID,每天一个 key，方便统计订单量
 */
@Component
public class RedisIdWorker {
    private static final long BEGIN_TIMESTAMP = 1752451200;  // 2025.7.14 0点0分的秒数
    private static final int COUNT_BITS = 32;  // 序列号的位数
    private final StringRedisTemplate stringRedisTemplate;

    public RedisIdWorker(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }

    public long nextId(String keyPrefix) {
        // 时间戳+序列号
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond- BEGIN_TIMESTAMP;
        //2.生成序列号
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        Long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);

        return timestamp << COUNT_BITS | count;  //先向左移空出位置，再进行或运算
    }
    public static void main(String[] args) {
        LocalDateTime time=LocalDateTime.of(2025,7,14,0,0,0);
        long second = time.toEpochSecond(ZoneOffset.UTC);
        System.out.println("second = "+second);
    }
}
